This section of this document introduces various concepts of the art that may provide context or be related to various aspects of the present invention described and/or claimed below. It provides background information to facilitate a better understanding of the various aspects of the present invention. As the section's title implies, this is a background discussion of “related” art. That such art is related in no way implies that it is also “prior” art. The related art may or may not be prior art. The discussion in this section of this document is to be read in this light, and not as admissions of prior art.
In military or police crowd control situations, particularly in riot or violent confrontations with large numbers of people it is often desirable but not practical to identify all participants. The mob members will disperse unless physically restrained and it is not possible to easily identify a person at a later time as having been involved in the act. In some situations it is desirable to covertly mark subjects with a material which will allow them to be later identified.
The present invention is directed to resolving, or at least reducing, one or all of the problems mentioned above.